Civil aircraft gas turbine engines are mounted to aircraft sub-structures through a pylon. The engines typically comprise an engine core surrounded by an aerodynamic nacelle. A fan at the engine inlet pushes a large volume of air through a bypass duct defined between the engine core and the nacelle. The pylon extends through the bypass duct and is located within an aerodynamically formed fairing that is known in the industry as a bifurcation that smooths the air flow through the bypass duct around the mounting structure.
The nacelles typically have cowls that move relative to the engine core to allow access to the engine core. The cowls are arranged to abut fixed sections within the engine and a seal is required between the fixed section in the bypass duct and the cowl.
Cowling doors can be large components and forming a repeatable seal that can be made, broken and remade has proved difficult. In particular, rigidly fixing the bifurcation aerofoil to the engine structure can, when the cowl doors are closed, lead to gaps giving poor sealing between the bifurcation aerofoil and the cowl door, or excessive pressure on the bifurcation leading edge that can damage the component. The radial join and existing manufacturing and assembly tolerances along with aero and inertia loads creates steps and gaps that are significant drag generators to the flow in the bypass duct.
It is an object of the present invention to seek to provide an improved sealing arrangement.